The present invention relates to an improved bell fountain cup. More particularly, the present invention relates to a plastic bell fountain cup which is more visually appealing than prior art plastic bell fountain shaped cups.
Bell fountain cups have been known for many years. A bell fountain cup has a bottom surface and a side wall extending upwardly from the bottom surface. The side wall has a lower side wall portion located adjacent the bottom surface, a radially outwardly expanded or bell-shaped portion, and an upper lip portion which defines a top opening of the cup. The bottom surface has a diameter smaller than a diameter of the top opening. The radially outwardly expanded portion has a diameter larger than the top opening diameter. Therefore, the cup is generally bell-shaped. Traditionally, these bell fountain cups were made from glass. However, it is desirable to replicate these glass bell fountain cups using a plastic material.
Plastic bell fountain cups have been made using standard injection molding techniques. However, the use of standard injection molding techniques requires that the side wall thickness in the area of the radially outwardly expanded bell-shaped portion of the cup be substantially thicker than the side wall thickness in the upper lip portion of the cup in order to permit the cup to be removed from a standard injection mold. This thicker plastic material in the radially outwardly expanded portion of the cup makes the plastic cup formed using standard injection molding techniques less visually appealing than glass cups, especially in the area of the bell-shaped portion which has the increased plastic thickness. This disadvantage is especially noticeable for clear plastic cups.
Advantageously, the bell fountain cup of the present invention is made using an injection stretch blow molding apparatus. This injection stretch blow molding apparatus advantageously permits the cup to have a substantially uniform side wall thickness throughout the lower portion of the side wall, the radially outwardly expanded bell-shaped portion, and at least a part of the upper lip portion of the side wall. This improves the aesthetic qualities of the cup by providing a very clear plastic material throughout the plastic bell fountain cup. Advantageously, there is no build-up of plastic in the radially outwardly expanded bell-shaped portion of the improved bell fountain cup of the present invention.
According to one aspect of the present invention, a plastic bell fountain cup includes a bottom surface, and a side wall formed integrally with and extending upwardly from the bottom surface. The side wall has a lower portion adjacent the bottom surface, an upper lip portion defining a top opening of the cup, and a radially outwardly expanded portion located between the lower portion and the upper lip portion. The radially outwardly expanded portion has a maximum diameter larger than a diameter of the bottom surface and larger than a diameter of the top opening. The side wall has a substantially uniform thickness throughout the lower portion, the radially outwardly expanded portion, and at least a part of the upper lip portion.
In the illustrated embodiment, the side wall of the plastic bell fountain cup has a thickness of about 0.020 inch (0.508 mm). The side wall thickness varies by about +/-0.005 inch (0.127 mm) throughout the lower portion, the radially outwardly expanded portion, and at least said part of the upper lip portion. The side wall thickness varies by about +/-0.002 inch (0.0508 mm) in the radially outwardly expanded portion.
According to another aspect of the present invention, a method is provided for making a plastic bell fountain cup. The method comprising the steps of expanding a plastic preform in a mold using injection stretch blow molding to form a bottom surface, and a side wall formed integrally with and extending upwardly from the bottom surface. The side wall has a lower portion adjacent the bottom surface, an upper lip portion defining a top opening of the cup, and a radially outwardly extending portion located between the lower portion and the upper lip portion above the base. The radially outwardly expanded portion has a maximum diameter larger than a diameter of the bottom surface and larger than a diameter of the top opening. The side wall has a substantially uniform thickness throughout the lower portion, the radially outwardly expanded portion, and at least a part of the upper lip portion.
Another advantage of the present invention is that the use of an injection stretch blow mold method uses substantially less material than conventional injection molding methods. This results in a substantial cost savings. In the present invention, the side wall thickness is about 0.020 inch (0.508 mm). Injection molding methods require a side wall thickness of at least about 0.040 inch (1.016 mm) with a much thicker bulge area as discussed below.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.